Venezuelan President Hugo Chávez is on artificial respiration after undergoing a tracheotomy earlier this week, according to the Madrid-based publication ABC.

Chávez has been suffering from complications after his fourth surgery in Havana, Cuba to treat cancer. Doctors performed the tracheotomy after a respiratory infection blocked the leader’s breathing, ABC reported. The procedure involves opening a hole in the neck so the patient can breathe without using the nose or mouth.

Venezuelan Vice President Nicolás Maduro has summoned several Chavista leaders to Havana, the Spanish publication reported.